This disclosure relates to the bonding and grounding of solar photovoltaic (PV) panels or solar hot water panels, herein collectively referred to as solar panels, to mounting rails or racking system, mounting clamps, and other mounting components that together comprise a solar panel system.
Solar panel systems can be rooftop or ground mounted, using rails, clamps, and adaptors held with bolts and nuts. Good engineering practice as well as the electrical codes in many locations requires, for the purpose of safety and lightning protection, that the solar panels, rails, and other components be bonded electrically together and then electrically grounded. Many solar panel systems use aluminum components for the rails, splices, mounting clamps, and panel frames. These aluminum components can be anodized to protect their finish from the elements. While aluminum is a good electrical conductor, the anodized surfaces of the aluminum components are electrical insulators. For the purpose of bonding and grounding, these anodized surfaces must be penetrated in order to obtain a good electrical connection. Alternatively, solar panel systems can use steel racking components instead of aluminum. The surfaces of the steel racking components may be galvanized or painted, or alternatively may become oxidized. While steel is an electrical conductor, the above-mentioned surfaces can act as electrical insulators. As with the aluminum rail systems, for the purpose of bonding and grounding, these steel surfaces must be penetrated in order to obtain a good electrical connection.
At present, many installers electrically connect the chassis of each solar panel together by connecting a large gauge copper conductor to each solar panel by a lug, screw, or similar fastener. Star washers, and more recently, specially formed washers can be installed between the solar panels and the rails. These washers include serrations that penetrate the anodized surfaces of both the solar panel and the rail system thereby electrically bonding the solar panel and rail system to each other. This approach can have shortcomings and disadvantages. For example, extra parts must be counted out, carried to the installation site or onto a rooftop, inserted in the correct order, and aligned correctly to perform the function of effectively bonding and grounding the components of the solar panel system. Often these tasks are performed under adverse conditions, for example, on steep rooftops and while wearing gloves and other safety equipment.